Metal and non-metal (i.e., polymeric) projectiles are known. For example, U.S. Pat. No. 5,237,930 (Belanger et al.) discloses projectiles comprising a thermoplastic material (i.e., polyamide) matrix filled with copper powder. The resulting “frangible projectiles” possess (1) similar ballistic effects as conventional projectiles, and (2) the ability to disintegrate upon impact with a hard surface.
Using a similar powder metallurgy concept, U.S. Pat. No. 6,074,454 (Abrams et al.) and U.S. Pat. No. 6,090,178 (Benini) proposed to make a similar projectile, but used only metal powder without any kind of polymeric binder, sintered by itself.
Furthermore, U.S. Pat. No. 6,149,705 (Lowden et al.) and U.S. Pat. No. 6,263,798 (Benini) disclosed applying a powder metallurgical manufacturing concept projectile again, by joining metal powder together via another metal, as a binder, with lower melting temperature, in an attempt to emulate the original work of Belanger et al. without sintering and without non-metallic material processing.
Finally, U.S. Pat. No. 6,546,875 (Vaughn et al.) disclosed a design and manufacturing method of a hollow-point projectile without using lead. The disclosed design included a hollow tip made of monolithic tin in combination with a powder metallurgic component around the monolithic tin to give weight to the projectile with all comprised in a coating of copper or brass.
In view of prior projectile developments, the present inventors continued efforts to develop projectiles with the goal of developing a projectile (e.g., metal and/or non-metal) that would harness both the kinetic and rotational energy imparted on the projectile in the process of firing. The development took into account: (1) the material(s) used to form the projectile, knowing that, in some cases (e.g., a polymer filled with metal particles), the material(s) would be relatively light and the resulting projectile would travel at a higher velocity and spin much faster than conventional bullets; (2) velocity and revolutions per minute (or second) of the resulting projectile; (3) the ability of the projectile shape to disrupt soft tissue even when using lower than normal bullet mass; (4) the need for the bullet to be able to be fed reliably into a wide variety of firearms on the market (e.g., pistols, air guns, rifles, machine guns, etc.); (5) the target accuracy of the resulting projectile upon firing from a weapon, and the development of correct projectile diameters and base configurations to deliver peak accuracy; and (6) barrel wear on the firearm due to the projectile design/materials.